Table 2 Different Doppler parameters and explanation.
Abbreviation | Full term | Equation/explanation | Synonym |
|---|---|---|---|
RI | Resistance index | Vs − Vd/Vs | Pourcelot index Resistency index |
PI | Pulsatility index | Vs − Vd/MV | |
MV | Mean velocity | Mean velocity calculated over a series of cardiac cycles | |
Vps | Peak-systolic velocity | Highest velocity in the cardiac cycle | Vs |
Ves | End-systolic velocity | Velocity at the end of the systolic phase of cardiac cycle | |
Ved | End-diastolic velocity | Lowest velocity in the cardiac cycle | Minimum CBFV Vd |
AUVC | Area under the velocity curve | Represents mean flow velocity | |
CBFF | Cerebral blood flow fluctuation | Interquartile range of velocity | |
Min–max MV ratio | Ratio of minimum and maximum MV | Minimal MV/maximal MV | |
Vmean ratio | Ratio of VM at different times | MV in first 12 h/MV at 12–168 h | |
TAV | Time averaged velocity | Vmax/2 | |
CV% | Coefficient of variability | Coefficient of variation of AUVC values of 20 consecutive cardiac cycles | |
BFV | Blood flow velocity | ||
Cerebrovascular perfusion pressure | Mean BFV/(mean BFV − diastolic BFV) × (mean BP − diastolic BP) | ||
Cerebral blood flow resistance | Cerebral perfusion pressure/RI |
